Scale errors in flow measurement

Rotameters, velocity flowmeters, and electromagnetic flowmeters have the advantage that they can be used with a linear scale in which the volumetric flow rate Q is directly proportional to the scale reading s. 

Let As be the indicator or recorder error. Then, for small errors 

Substituting equation 8.40 for a linear scale into equation 8.45 gives 

If the maximum volumetric flow rate Qmax =100 and the maximum scale reading smax = 100, equation 8.46 can be written as 

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